It is not beyond the realms that Australia go into the first Test in Adelaide with one opener who wasn't in the squad two days ago and another who has never done it in Test cricket.

As far as the top of the order goes, it has been a chaotic week or so. David Warner and the uncapped Will Pucovski are both ruled out - the latter perhaps more likely to feature on Boxing Day than the former - and the other incumbent Joe Burns has barely been able to score a run. He has been dusted up by the attack he would face on Thursday, and the man who appears most likely to play, Marcus Harris, is returning to the side after a gap of 16 months.

Moments after Burns walked off the field on Sunday, pinned lbw by Mohammed Shami, following the dismissal of Harris, cameras panned to national selector Trevor Hohns on the phone. He has been a busy man and the toughest call may be yet to come. Justin Langer and Tim Paine will hope a sense of order emerges over the next few days in Adelaide, which involves a day off on Monday, an intense training session on Tuesday and lighter work on Wednesday before Paine and Virat Kohli (in his last assignment of the tour) head out for the toss on Thursday afternoon.

"There is some pressure on him, no doubt," Chris Rogers, part of the Australia A coaching staff, said of Burns before his second innings at the SCG. "He's not stupid. So he has to make the most of this opportunity, that's pretty important, and then it's up to the selectors."

There has been some good news for Australia with Mitchell Starc rejoining the squad on Monday following his compassionate leave due to a family illness - he is a formidable threat with the pink ball - and Cameron Green, the uncapped allrounder, will travel to Adelaide having made promising progress after the blow on the head in his follow through at the SCG which left him with a mild concussion.

However, given the tight time frame, it is far from certain that Green will be ready to be in contention. Before these Australia A matches it felt unlikely he would make his debut early in the series, but such have been the issues at the top of the order that one of the options gaining traction is a promotion to open for Marnus Labuschagne (or even Matthew Wade) which then creates a natural vacancy for Green at No. 6.

He made a very fine 125 against the Indians at Drummoyne Oval, and while he is still restricted to four-over spells, he is chipping out wickets. However, under lights, it's unlikely Australia's big three quicks (alongside Nathan Lyon who has an impressive record with the pink ball) would need too much support. Green would have earned selection as a batsman.

That, though, relies on him clearing the various concussion protocols and a return to full training. Former Australia doctor Peter Brukner suggested on Saturday that the turnaround would probably be too tight.

Where that leaves Australia remains unclear. As yet they have not pressed the full panic button and summoned someone from outside the A-team that has been in Sydney. But the call will have to be taken if Burns remains unselectable.

"That's where Joe Burns is at with his technique at the moment - he is just shot. It's a sad sight, isn't it, seeing a bloke really struggling to find any sort of form," former Australia captain Allan Border told Fox Cricket after the dismissal against Shami.

"My gut feel is just no [for Burns]. He has been given these little windows of opportunity because of injury, concussion, circumstances with other guys without nailing down a spot," Border said. "If he had just shown something, even if he had 20-odd today and batted okay and got a good ball to get out - you might think: 'Okay, we'll stick with the incumbent'."

The members of the Test squad already in Adelaide have been having centre-wicket practice at the ground with a handful of them - including Pat Cummins and Josh Hazlewood - having played no long-form cricket since the first week of January.

"It's been an unusual one, a different lead-in for everyone, guys playing Shield, IPL then we've started with one-day cricket and T20," Hazlewood said. "Every international cricketer is prepared for that, they know the things they have to tick off and we've had a really good leading up here, a few days out on Adelaide Oval, and we've still got a number of sessions to go before the game."

Whether those sessions are enough for Burns, or if a decision has already been made, is the big question.